go-programming

name	go-programming
description	Go development guidance for creating, modifying, reviewing, testing, and debugging Go services, libraries, CLIs, and tooling. Use when tasks involve .go files, go.mod, go.work, goroutines, channels, contexts, HTTP handlers, database code, table tests, gofmt, go test, or Go module management.

Go Programming

Goal

Make idiomatic Go changes with small APIs, explicit errors, and verification through the standard toolchain.

Discovery

• Read go.mod, go.work, build tags, Makefiles, CI, and package layout before choosing commands or dependencies.
• Inspect nearby packages and tests to infer naming, error wrapping, logging, context use, and dependency injection style.
• Preserve public API compatibility unless the user explicitly requests a break.

Implementation

• Keep packages cohesive and avoid utility packages unless the repo already uses them.
• Return errors explicitly; wrap with context where the caller needs it.
• Pass context.Context through request, database, network, and long-running operations.
• Keep interfaces small and define them near the consumer.
• Use goroutines, channels, mutexes, and wait groups only when concurrency is needed and lifecycle/cancellation are clear.
• Avoid global mutable state; if unavoidable, isolate it and protect concurrent access.
• Run gofmt on changed Go files.

Testing

• Prefer table-driven tests for branching behavior.
• Use existing test helpers and fixtures before inventing new ones.
• Run targeted go test ./path/... first, then broader go test ./... when the change affects shared packages.
• Consider go test -race for concurrency changes and go vet or configured linters when the project already uses them.

Review Focus

• Missing context cancellation, goroutine leaks, unchecked errors, nil pointer paths, data races, unintended exported symbols, and accidental changes to module files.